In recent years, centrally in the fields, such as an optical lens, a plasma display panel (PDP), a cathode-ray tube display device (CRT), and a liquid crystal image display device of a computer and a word processor, there is proposed an antireflection film having an antireflection layer to reduce surface reflection in order to improve transmittance and contrast and to reduce taking a picture. As an antireflection layer, it is effective to reduce light reflex in a surface boundary between a laminated body and air by a lamination of several layers having proper values of refractive index and optical layer thickness as an optical interference layer. As the optical interference layer, there is provided a low refractive index layer and SiO2 and MgF2 are employed as low refractive index materials.
Although an antireflection film can be produced by a dry type film forming method and a coating type film forming method, the coating type film forming method is generally used from the advantages being easy and cheap. Moreover, in order to provide performances such as scratch resistance and abrasion resistance to an antireflection film, the antireflection film is generally provided with hard coat property in such a way that a hard coat layer is formed as an interlayer on a film base material. The hard coat layer is generally structured with a ultraviolet curable resin, and for example, a ultraviolet curable type (meth)acrylate monomer having a (meth)acrylyl group is used as the ultraviolet curable resin. Further, for the hard coat layer, in order to obtain a uniform surface and to prevent surface defects such as repelling and voids, a fluorine or silicone surfactant having an effect to greatly reduce the surface tension of a coating liquid is employed. However, the hard coat layer in which the (meth)acrylate monomer and only the fluorine or silicone surfactant are used has the following problems. For example, a hard coat film is preserved in a rolled state, and thereafter, the hard coat film is rolled off from the rolled state and an antireflection film is formed in such a way that an antireflection layer is coated on the hard coat layer, In this case, the smoothness of the surface of the hard coat layer is lost, the surface orientation of the fluorine or silicone surfactant is influenced, and the adhesion between the antireflection layer and the hard coat layer decreases. As a result, the chemical resistance, the surface hardness and the moisture and heat resistance adhesion of the antireflection film decreases. These problems causes the reduction of commercial value and productivity.
Conventionally, the concomitant use of a fluorine or silicone surfactant and other surfactants makes the control of surface orientation difficult and also makes it difficult to maintain the stable coating properties of the hard coat layer. Further, it influences greatly the coating properties of an antireflection layer such as aggregation of metallic compounds. Therefore, it is technically difficult. Further, Patent Documents 1 and 2 describe about the technical difficulty of the concomitant use of a nonionic surfactant and a silicone surfactant.
Patent Documents 3 through 6, for example, disclose improvement techniques over the above theme. However, sufficient improvement effects are not acquired with the above techniques. Especially, in the case that an antireflection film is formed after a hard coat layer and a transparent film have been stored on a close contact condition, the improvement effects over the above theme, are not enough.
The present inventor found that when a polyoxy ether compound is used in combination with a silicone surfactant in a specific additive range, stable coating properties can be obtained and the above theme can be solved. As a result, the present inventor achieved the present invention.
There are no teachings about the compound of the present invention in Patent Documents 1 and 2, and Patent Documents 3 through 6 do not teach nor suggest about the above theme solution by the concomitant use of a silicone surfactant and a polyoxy ether compound.
Patent Documents 1: Japanese Patent Unexamined Publication No. 2005-186584
Patent Documents 2: Japanese Patent Unexamined Publication No. 2004-114355
Patent Documents 3: Japanese Patent Unexamined Publication No. 2001-74909
Patent Documents 4: Japanese Patent Unexamined Publication No. 2001-74910
Patent Documents 5: Japanese Patent Unexamined Publication No. 2001-76647
Patent Documents 6: Japanese Patent Unexamined Publication No. 2004-212619